Five-term incumbent Sen. John McCain (R-AZ)45% has good reason to fear a primary challenge. Newly released data from liberal-leaning Public Policy Polling shows half of Arizona’s Republican primary voters disapprove of McCain’s job performance, and more than half would prefer a more conservative Senate candidate in 2016.

After more than three decades in Washington, McCain earns merely 41 percent approval from Arizona Republicans and 36 percent from general Arizona voters, PPP finds. Just 37 percent reported a willingness to support the Senator in his 2016 re-election bid.